The vision is the most direct and important way for human to observe recognize our world. We are living in a three-dimensional world, and the human vision can not only perceive the brightness, color, texture information and movement on the surface of an object, but also distinguish its shape, space and spatial position (depth and distance). Currently, the difficulty in researching the machine vision system is how to acquire the high-precision 3D depth information in a real time and improve the intelligent level of the machine.
In the field of industry, high-resolution and high-precision 3D depth information is widely demanded, such as automotive safety driving assisting, high-speed machine tool processing, industrial modeling, 3D printing, medical imaging and 3D visual perception in the IOT (Internet of Things). In the field of consumer electronics, the depth perception technology and devices can help to improve the intelligent level and interaction ability of electronic products so as to bring “fiction-like” control methods and brand-new man-machine interaction experience for users and achieve innovative applications in the smart TV, smart phones, household appliances, and tablet PC, etc.
Compared with the traditional binocular stereoscopic cameras, the active visual mode based on structured light coding can get image depth information more accurately, stably and reliably, featuring such advantages as no impact of the ambient light, simple stereoscopic matching process and small calculation amount of the algorithm. For example, the somatosensory interaction device of MICROSOFT-KINECT adopts the active visual mode of infrared structured light, namely, the infrared laser projects a fixed image onto the surface of an object to form scattered spots via diffuse reflection on the surface, and the imaging sensor acquires speckle images to obtain the depth information of the object by means of calculation via the image depth sensor chip.